diff --git a/CHANGELOG.md b/CHANGELOG.md
index b103992..c6dbb03 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [6.6.0] - 2026-07-01
+### Added
+- Added retention draft methods: `UpdateDraftAsync`, `StampDraftAsync`, and `CopyToDraftAsync`.
+
 ## [6.5.0] - 2026-06-07
 ### Added
 - Expose structured API error metadata on `FacturapiException`, including `Code`, `Path`, `Location`, `Errors`, `LogId`, and response `Headers`.
diff --git a/FacturapiTest/WrapperBehaviorTests.cs b/FacturapiTest/WrapperBehaviorTests.cs
index f03fddb..b433691 100644
--- a/FacturapiTest/WrapperBehaviorTests.cs
+++ b/FacturapiTest/WrapperBehaviorTests.cs
@@ -263,6 +263,108 @@ public async Task RetentionListAsync_UsesRetentionsRoute()
             Assert.NotNull(result.Data);
         }
 
+        [Fact]
+        public async Task RetentionListAsync_CanFilterDrafts()
+        {
+            var handler = new RecordingHandler((request, cancellationToken) =>
+            {
+                Assert.Equal(HttpMethod.Get, request.Method);
+                Assert.NotNull(request.RequestUri);
+                Assert.Equal("/v2/retentions?status=draft", request.RequestUri.PathAndQuery);
+                return Task.FromResult(JsonResponse("{\"data\":[]}"));
+            });
+
+            var wrapper = new RetentionWrapper("test_key", "v2", CreateHttpClient(handler));
+            var result = await wrapper.ListAsync(new Dictionary<string, object> { ["status"] = "draft" });
+
+            Assert.NotNull(result);
+            Assert.NotNull(result.Data);
+        }
+
+        [Fact]
+        public async Task RetentionCreateAsync_CanCreateDraft()
+        {
+            var handler = new RecordingHandler(async (request, cancellationToken) =>
+            {
+                Assert.Equal(HttpMethod.Post, request.Method);
+                Assert.NotNull(request.RequestUri);
+                Assert.Equal("/v2/retentions", request.RequestUri.PathAndQuery);
+                Assert.NotNull(request.Content);
+                var body = await request.Content.ReadAsStringAsync().ConfigureAwait(false);
+                Assert.Contains("\"status\":\"draft\"", body);
+                Assert.Contains("\"customer\":null", body);
+
+                return JsonResponse("{\"id\":\"ret_123\"}");
+            });
+
+            var wrapper = new RetentionWrapper("test_key", "v2", CreateHttpClient(handler));
+            var result = await wrapper.CreateAsync(new Dictionary<string, object>
+            {
+                ["status"] = "draft",
+                ["customer"] = null!
+            });
+
+            Assert.Equal("ret_123", result.Id);
+        }
+
+        [Fact]
+        public async Task RetentionUpdateDraftAsync_UsesRetentionRoute()
+        {
+            var handler = new RecordingHandler(async (request, cancellationToken) =>
+            {
+                Assert.Equal(HttpMethod.Put, request.Method);
+                Assert.NotNull(request.RequestUri);
+                Assert.Equal("/v2/retentions/ret_123", request.RequestUri.PathAndQuery);
+                Assert.NotNull(request.Content);
+                var body = await request.Content.ReadAsStringAsync().ConfigureAwait(false);
+                Assert.Contains("\"folio_int\":\"R-2026-001\"", body);
+
+                return JsonResponse("{\"id\":\"ret_123\"}");
+            });
+
+            var wrapper = new RetentionWrapper("test_key", "v2", CreateHttpClient(handler));
+            var result = await wrapper.UpdateDraftAsync("ret_123", new Dictionary<string, object>
+            {
+                ["folio_int"] = "R-2026-001"
+            });
+
+            Assert.Equal("ret_123", result.Id);
+        }
+
+        [Fact]
+        public async Task RetentionCopyToDraftAsync_UsesCopyRoute()
+        {
+            var handler = new RecordingHandler((request, cancellationToken) =>
+            {
+                Assert.Equal(HttpMethod.Post, request.Method);
+                Assert.NotNull(request.RequestUri);
+                Assert.Equal("/v2/retentions/ret_123/copy", request.RequestUri.PathAndQuery);
+                return Task.FromResult(JsonResponse("{\"id\":\"ret_copy\"}"));
+            });
+
+            var wrapper = new RetentionWrapper("test_key", "v2", CreateHttpClient(handler));
+            var result = await wrapper.CopyToDraftAsync("ret_123");
+
+            Assert.Equal("ret_copy", result.Id);
+        }
+
+        [Fact]
+        public async Task RetentionStampDraftAsync_UsesStampRoute()
+        {
+            var handler = new RecordingHandler((request, cancellationToken) =>
+            {
+                Assert.Equal(HttpMethod.Post, request.Method);
+                Assert.NotNull(request.RequestUri);
+                Assert.Equal("/v2/retentions/ret_123/stamp", request.RequestUri.PathAndQuery);
+                return Task.FromResult(JsonResponse("{\"id\":\"ret_123\"}"));
+            });
+
+            var wrapper = new RetentionWrapper("test_key", "v2", CreateHttpClient(handler));
+            var result = await wrapper.StampDraftAsync("ret_123");
+
+            Assert.Equal("ret_123", result.Id);
+        }
+
         [Fact]
         public async Task ErrorMapping_UsesStatusFromString()
         {
diff --git a/Router/RetentionRouter.cs b/Router/RetentionRouter.cs
index 4f655ee..bf5d8ff 100644
--- a/Router/RetentionRouter.cs
+++ b/Router/RetentionRouter.cs
@@ -28,6 +28,21 @@ public static string CancelRetention(string id, Dictionary<string, object> query
             return UriWithQuery(RetrieveRetention(id), query);
         }
 
+        public static string UpdateDraftRetention(string id)
+        {
+            return RetrieveRetention(id);
+        }
+
+        public static string StampDraftRetention(string id, Dictionary<string, object> query = null)
+        {
+            return UriWithQuery($"retentions/{id}/stamp", query);
+        }
+
+        public static string CopyRetention(string id)
+        {
+            return $"retentions/{id}/copy";
+        }
+
         public static string DownloadRetention(string id, string format)
         {
             return $"retentions/{id}/{format}";
diff --git a/Wrappers/IRetentionWrapper.cs b/Wrappers/IRetentionWrapper.cs
index 9359c4d..31d05c7 100644
--- a/Wrappers/IRetentionWrapper.cs
+++ b/Wrappers/IRetentionWrapper.cs
@@ -12,6 +12,9 @@ public interface IRetentionWrapper
         Task<Invoice> RetrieveAsync(string id, CancellationToken cancellationToken = default);
         Task<Invoice> CancelAsync(string id, Dictionary<string, object> query = null, CancellationToken cancellationToken = default);
         Task SendByEmailAsync(string id, Dictionary<string, object> data = null, CancellationToken cancellationToken = default);
+        Task<Invoice> UpdateDraftAsync(string id, Dictionary<string, object> data, CancellationToken cancellationToken = default);
+        Task<Invoice> StampDraftAsync(string id, Dictionary<string, object> options = null, CancellationToken cancellationToken = default);
+        Task<Invoice> CopyToDraftAsync(string id, CancellationToken cancellationToken = default);
         Task<Stream> DownloadZipAsync(string id, CancellationToken cancellationToken = default);
         Task<Stream> DownloadPdfAsync(string id, CancellationToken cancellationToken = default);
         Task<Stream> DownloadXmlAsync(string id, CancellationToken cancellationToken = default);
diff --git a/Wrappers/RetentionWrapper.cs b/Wrappers/RetentionWrapper.cs
index 607d31e..157f0c9 100644
--- a/Wrappers/RetentionWrapper.cs
+++ b/Wrappers/RetentionWrapper.cs
@@ -69,6 +69,42 @@ public async Task SendByEmailAsync(string id, Dictionary<string, object> data =
             }
         }
 
+        public async Task<Invoice> UpdateDraftAsync(string id, Dictionary<string, object> data, CancellationToken cancellationToken = default)
+        {
+            using (var content = new StringContent(JsonConvert.SerializeObject(data), Encoding.UTF8, "application/json"))
+            using (var response = await client.PutAsync(Router.UpdateDraftRetention(id), content, cancellationToken).ConfigureAwait(false))
+            {
+                await this.ThrowIfErrorAsync(response, cancellationToken).ConfigureAwait(false);
+                var resultString = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
+                var retention = JsonConvert.DeserializeObject<Invoice>(resultString, this.jsonSettings);
+                return retention;
+            }
+        }
+
+        public async Task<Invoice> StampDraftAsync(string id, Dictionary<string, object> options = null, CancellationToken cancellationToken = default)
+        {
+            using (var content = new StringContent("", Encoding.UTF8, "application/json"))
+            using (var response = await client.PostAsync(Router.StampDraftRetention(id, options), content, cancellationToken).ConfigureAwait(false))
+            {
+                await this.ThrowIfErrorAsync(response, cancellationToken).ConfigureAwait(false);
+                var resultString = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
+                var retention = JsonConvert.DeserializeObject<Invoice>(resultString, this.jsonSettings);
+                return retention;
+            }
+        }
+
+        public async Task<Invoice> CopyToDraftAsync(string id, CancellationToken cancellationToken = default)
+        {
+            using (var content = new StringContent("", Encoding.UTF8, "application/json"))
+            using (var response = await client.PostAsync(Router.CopyRetention(id), content, cancellationToken).ConfigureAwait(false))
+            {
+                await this.ThrowIfErrorAsync(response, cancellationToken).ConfigureAwait(false);
+                var resultString = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
+                var retention = JsonConvert.DeserializeObject<Invoice>(resultString, this.jsonSettings);
+                return retention;
+            }
+        }
+
         private async Task<Stream> DownloadAsync(string id, string format, CancellationToken cancellationToken)
         {
             using (var response = await client.GetAsync(Router.DownloadRetention(id, format), cancellationToken).ConfigureAwait(false))
diff --git a/facturapi-net.csproj b/facturapi-net.csproj
index 5a243c5..a02772a 100644
--- a/facturapi-net.csproj
+++ b/facturapi-net.csproj
@@ -11,7 +11,7 @@
     <Summary>SDK oficial de Facturapi para .NET para facturación electrónica en México (CFDI), envío de documentos, búsqueda y trazabilidad.</Summary>
     <PackageTags>factura factura-electronica facturacion cfdi cfdi40 sat invoice invoicing facturapi mexico</PackageTags>
     <Title>Facturapi</Title>
-    <Version>6.5.0</Version>
+    <Version>6.6.0</Version>
     <PackageVersion>$(Version)</PackageVersion>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>